Prilled ammonium nitrate composition of improved anti-scattering properties

ABSTRACT

A prilled ammonium nitrate composition having blended with (1) a petroleum hydrocarbon having a boiling point of more than 150*C. and a melting point of less than 20*C. and (2) at least one anticoagulant selected from (a) magnesium, barium, lead, calcium, zinc, copper, aluminum and cadmium salts of fatty acid of seven to 22 carbon atoms and a melting point of more than 40*C., (b) magnesium aluminate silicate and (c) a compound of the formula:   , AND WHEREIN R1 and R3 each represent alkyl groups having 10 to 20 carbon atoms and R2 is an alkylene group having one to two carbon atoms, which composition is characterized by improved anti-caking and anti-scattering properties.

States Fnjiltietal.

[ Dec. 18, 1973 PRKLLED AMMONIUM NITRATE COMPQSITION OF IMPROVED ANN-SCATTERING PROPERTIES [73] Assignee: Mitsubishi Chemical industries Limited, Tokyo, Japan 122] Filed; Sept. 15, 1,972

[21] App]. No.: 289,729

[30] Foreign Application Priority Data Sept. 27, 1971 Japan 46/753311 [52] US. Cl. 149/7, 149/5, 149/46 [51] lint. Cl. C06b 1/04 [58] lField of Search 149/7, 46, 5

[56] References Cited UNITED STATES PATENTS 3,493,445 2/1970 Takata et a1 149/46 2,048,050 7/1936 Baker 149/46 X 2,072,719 3/1937 Pearsall.. 149/5 X 2,162,910 6/1939 Byers l 149/7 2,345,582 4/1944 Carey 149/7 X 2,407,151 9/1946 Glogan 149/5 3,039,903 6/1962 Enoksson 149/7 3,046,888 7/1962 Gordon 149/5 X 3,116,185 12/1963 Wilson et a1 149/7 3,223,478 12/1965 Wilson 149/46 3,287,189 11/1966 Wilson et a1 149/46 3,453,155 7/1969 Sheeran et a1 149/5 Primary Examiner-Stephen J. Lechert, Jr. Att0rney-Norman F. Oblon et a1.

[ 5 7] ABSTRACT A p rilled ammonium nitrate composition ha ving and wherein R and R each represent alkyl groups having 10 to 20 carbon atoms and R is an alkylene group having one to two carbon atoms, which composition is characterized by improved anti-caking and anti-scattering properties,

5 Claims, N0 Drawings PRILLED AMMONIUM NITRATE COMPOSITION OF IMPROVED ANTI-SCATTERING PROPERTIES BACKGROUND OF THE INVENTION 1. Field Of The Invention The present invention relates to a prilled ammonium nitrate composition having improved anti-caking and anti-scattering properties and to a method of making the same.

2. Description Of The Prior Art Ammonium nitrate is known to exist in several different crystalline structures, depending upon tempera- 'ture. Each of these structures are characterized by a different water solubility, specific volume and degree of hygroscopicity. As the ammonium nitrate is subjected to cycling across the crystal structure transition temperature, therefore, it experiences variations in solubilities, specific volume and hygroscopicity. If the ammonium nitrate is in the form of prills or small, spherical, usually hollow, particles, as are commonly used for various commercial and agricultural purposes, the prills tend to absorb increasing amounts of moisture from the air, and tend to cake into a non-flowable mass. In the past, it has been attempted to reduce this caking tendency by coating the prills with anti-caking agents, such as powdered talc, diatomaceous earth, talc or the like. The difficulty with the use of such conventional anti-caking agents, is that they cannot be completely and uniformly coated onto the prills. A portion of the powdered anti-caking agent will invariably remain unadhered to the prills. The presence of this powder results in reductions in operation efficiency and often creates sanitation difficulties.

It has been suggested to reduce the quantity of anticaking agent used so that it is entirely adhered to the prills. However, it has been found that such reductions will adversely reduce the effects of the agent in preventing caking.

A need continues to exist, therefore, for a prilled ammonium nitrate composition which is characterized by improved anti-caking properties and improved anti scattering properties.

SUMMARY OF THE INVENTION Accordingly, it is one object of the present invention to provide a prilled ammonium nitrate composition characterized by improved anti-caking and antiscattering properties.

Another object of the present invention is to provide a method of making the prilled ammonium nitrate composition having such improved anti-caking and antiscattering properties.

These and other objects of this invention, as will hereinafter become more readily understood, have been attained by blending prilled ammonium nitrate M l l a petroleum hydrocarbon having a boiling point of more than 150C. and a melting point of less than 20C. and

2. at least one anti-caking agent selected from the group consisting of:

a. magnesium, barium, lead, calcium, zinc, copper, aluminum, and cadmium salts of fatty acid having seven ro""22'a'rb'6a atoms ahd fin eltmg point of greater than 40C.;

b. magnesium aluminate silicate; and

c. a compound represented by the formula:

wherein R] and R} each represent alkyl groups having to carbon atoms and R represents an alkylene group having one to two carbon atoms.

Another object of this invention is accomplished by aaaiiirg *iafinezr'airrate'aasrammg Tie l0 pr'cnt'by weight of water, at a temperature of 40 to C., adding a drying aid, drying at a temperature higher than said aerating temperature and blending the obtained granular ammonium nitrate with:

"" pefrolum hydrocarbbnhaving a boiling point of more than C. and a melting point of less than 20C. and

2. at least one anti-caking agent selected from the group consisting of:

a. magnesium, barium, lead, calcium, zinc, copper, aluminum, and cadmium salts of fatty acid having seva'rai'z' carb dii' arms afia "azirrag'asrni of more than 40C.; w I '4 "id FF 7 b. magnesium aluminate silicate; and

c. a compound represented by the formula:

, wherein R R and R are as defined above.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a particular petroleum hydrocarbon and anti-caking agent are blended with prilled ammonium nitrate.

The petroleum hydrocarbon used herein should have a bom ng point of greafer thanm c farid a r neitirfg point of less than 20C., preferably less than 0C. Suitable hydrocarbons include the distillates having average boiling points of 200 to 300C. obtained by atmospheric distillation of crude oil; the liquid paraffins pre pared by dewaxing a wax containing fraction obtained by vacuum distillation of paraffinic crude oil; the processing oils, such as cutting oil, quenching oil, etc.; the light lube oils, such as spindle oil, refrigerating oil, turbine oil, etc., and mixtures thereof. Petroleum hydroc afbons having melting points of more than 20C. are

not desirable, since their antiscattering effects are low. It is believed that the poor results obtained with such hydrocarbons is a result of the fact that they are easily solidified after being added to the prilled ammonium nitrate. Petroleum hydrocarbons having boiling points of below 150C. are not desirable in practical situations because they are largely lost when the treated prills are dried.

If the quantity of the petroleum hydrocarbon used is too small, the quantity of anti-caking agent adhering to the prilled ammonium nitrate will be too low and the anti-scattering effect of the agent will be too small. On the other hand, if the quantity of additive is too large, the prilled ammonium nitrate admixed with the additive will be so wet that handling can become difficult. Therefore, it is desirable to use the petroleum hydrocafbo n in amounts of from 0.05 to 1.0 percent 52155 on the weight of the prilled ammonium nitrate.

The anti-caking agent used in the present invention may be selected from at least one of:

a. magnesium, barium, lead, calcium, zinc, copper, aluminum, cadmium salt of fatty acid having a carbon atom content of seven to 22, and a melting point of se@ I.th n.42i --M..-

b. magnesium aluminate silicate; and

c. a compound represented by the formula:

, wherein R R and R are as defined above. The salts of group (a) are most preferred.

Suitable salts of group (a) include magnesium stearate, barium stearate, zinc oleate, copper palmitate, aluminum stearate, cadmium oleate, calcium stearate, magnesium oleate, etc. Magnesium stearate is most preferred. The metallic salts of fatty acids having carton contents of less than six carbon atoms, or melting points of below 40C., are not desired since their anticaking effects are low and/or they tend to melt due to the rising of temperature during storage so that caking of the prilled ammonium nitrate can occur.

Suitable compounds of group (c) include, for example, methylene bispalmitylamide, methylene bisstearoamide, ethylene bis-stearoamide, a formaldehyde condensate of palmitic acid amide and stearic acid amide, etc. or mixtures thereof.

When the quantity of anti-caking agent blended therewith is too small, sufficient anti-caking effects cannot be obtained. If excess amounts are used, no significant improvements in anti-caking effects and antiscattering effects can be expected. When using prilled ammonium nitrate as a raw material for producing such explosive compounds as ANFO, a large excess of anticaking agent is actually detrimental, since it can result in reductions in explosive efficiency. For most commercial purposes, it is desirable to use the anti-caking agent in amounts of from 0.01 to 0.5 percent, based on the weight of the prills.

Two methods are here disclosed for blending the prilled ammonium nitrate with the petroleum hydrocarbon and the anti-caking agent:

1 the petroleum hydrocarbon is first dsitributed and homogeneously mixed withe the prilled ammonium nitrate in an available mixer, such as a rotary drum, and subsequently the anti-caking agent is distributed and mixed thereto in the same manner;

2. the petroleum hydrocarbon and anti-caking agent are simultaneously distributed and mixed homogeneously with the granular or prilled ammonium nitrate.

The prilled ammonium nitrate used in the present invention, may be either high density or low density prilled ammonium nitrate. However, the latter is more preferable when the prills are being used as raw materials in the preparation of such explosive compounds as ANFO. The lower the water content, the greater will be the anti-caking properties of the prilled ammonium nitrate. Normally, the prills are obtained by spraying a molten ammonium nitrate containing, for example, 2 to 10 percent, by weight, of water from the top of a prilling tower of several tens meters in height. The prills are then dried at a temperature of 80-l20C. to

btainalow wateracontent.

One method of efficiently drying the prills is, for example, to aerate the prills in an atmosphere of an inert gas, for example air, at a temperature of 40to 90C. and then, if necessary, adding a drying agent and subjecting the prills to an aging treatment. Good results are attainable if the aeration is carried out at a temperature of 40 to C., preferably 60 to 90C. If the temperature is lower than 40C. drying of the granulate will not be sufficiently complete. If higher temperatures are used, no significantly better results will be expected and it will merely be economically disadvantageous from the viewpoint of energy consumption. Aeration usually requires more than 5 minutes, and preferably between about 10 to 30 minutes. One method of effecti r ig the above aeration, is for example, to place the ammonium nitrate onto a perforated plate, and fluidize it by air blasts from an aperture. Another suitable method is to pass the ammonium nitrate on a moving belt through an aeration room. Still another method is to pass air into a rotating rotary containing the prills. Of course, any conventional technique is also suitable. Suitable inert gases which can be used in this treatment include air, nitrogen, carbon dioxide, etc., although it is generally sufficient to use air. The required rate of inert gas is commonly greater than 10 cm/sec., and preferably within the range of to 300 cm/sec. Although the lower the relative humidity of the inert gas the better it is, the relative humidity need only be below the critical humidity of the prilled ammonium nitrate. The favorable effect of aeration treatment is believed to be due to the fact that a relatively large size (10 to 20p.) aperture is formed on the surface layer of the ammonium nitrate particles due to the contact with inert gas. The permeation of the drying aid into the interior of the ammonium nitrate particle, therefore, is quite easy. The aerated prill is preferably subsequently admixed with the drying aid.

Suitable drying aids used herein include, for example,

1. the amines represented by the formula:

RNH

(wherein R represents a saturated or unsaturated chain y sa adiwlbavins eiehttq ..8..qetbq at m or its derivative, or, forms an inorganic or organic salt of said amines, preferably an amine nitrate;

me lammqn u eret rq sntes tby the formula:

, wherein R R and R each represent methyl or ethyl, and X represents chlorine or bromine, and R is as defined above;

3. polyoxyethylene alkyl ethers represented by the formula:

, wherein R is as defined above, and n is an integer of one to 20;

4 polyoxyethylene alkyl phenylethers represented by the formula:

m-Qo-wanonn wherein R is an alkyl group having eight to nine carbon atoms;

5. sulfuric acid ester salts of higher alcohols, represented by the formula:

ROSO Na wherein R is as defined above;

7. polyoxyethylene sorbitane alkyl esters;

8. poiyoxyethylene oxypropylene triols;

9. hydroxyethylene hydroxypropylene triols;

10. alkyl pyridinium salts;

11. higher fatty acid amide sulfonate;

12. higher fatty acid esters of polyethyleneglycol;

13. higher fatty acid esters of sorbitane;

l4. polyoxyethyiene alkylamine;

15; a betaine type of amphoteric surface active agent;

16 an acyl pyridinium salt; and mixtures thereof.

Prilled ammonium nitrate is prevented from partially powdering during the drying step by using one of these drying a ids. i a rticuiarly good results are attained with alkylamine orits saltsfshown in (1) The result is that prilled ammonium nitrate having improved antiscattering property is obtained, in good yields.

Exemplary of suitable drying agents include dodecylamine or its nitrate, octadecyiamine or its nitrate, lauryltrimethylammonium-chloride, poiyoxyethylenestearylether, polyoxyethyleneoctylether, polyoxyethylene nonyiether, polyoxyethylene sorbitane monooleate, laurylpicolinium chloride, sodium iaurylsulfate, sodium octylsulfate, polyoxyethylene octylamide, polyoxyethylene stearylamide, oleic acid amide, sodium sulfonate, polyethyleneglycoi monostearate, sorbitan monostearate, poiyoxyethylene octadecylamine, laurylbetain, acetylpyridium chloride, etc.

Although these drying agents may be used in any concentration in a solution, such as, for example, an aqueous solution, alcohol solution, or benzene solution, they are desirable used as a solution in amounts of l to percent, by weight, in concentration, in order to be uniformly distributed over the ammonium nitrate. The amount of drying aid should be added in amounts of from 0.01 to 1.0 percent and preferably 0.02 to 0.06 percent based on the weight of the prilled ammonium nitrate. If one of the above alkylamines or salts thereof are used, it is used in amounts of 0.2 to 0.5 percent, by weight. The drying aid may be introduced by being sprayed onto the particle surface of the prilled ammonium nitrate. This is accomplished, generally in a suitable mixer, such as a rotary drum, or the like. This spray adding may be carried out stepwise, once, twice,

or more times, in order to permeate the solution of the drying agent sufficiently into the interior of entire particles. Further, the addition of the drying agent may be done either immediately after the aeration treatment, i.e., while the particles are still at elevated temperatures, or after the particles are cooled to room temperatures.

When the above prill is subjected to aging treatment after admixing the drying agent therewith, the water content of the prilled ammonium nitrate becomes greatly reduced. The purpose of the aging treatment is to permeate the drying agent from the surface of the ammonium nitrate prill sufficiently into the interior thereof. Aging is preferably effected by stirring or mixing the pai'ireias'w i'th the drying aid, using, for instance, a rotating vessel or the like in the absence of air. The aging treatment is preferably carried out at tempera tures of to 80C. for about 5 to 30 minute s.

As described above, after aeration, the prilled ammonium nitrate which has been admixed with the drying agent and, if necessary, has been aging treated, is subjected to further drying. This drying treatment is preferably eminent at ternpe ratu rs of froin to 100C., or higher than that in the above aeration treatment, for 10 to 30 minutes. This step should preferably be carried out by fluidizing the particles in an atmosphere of inert gas, such as air, nitrogen, or carbon dioxide. The veiocity ofthe gas shouldbe g r eater than 10 cm/sec., and, preferably, between 100 and 300 cm/sec.

The present invention will now be further illustrated by reference to the following Examples by which the present invention is not intended to be limited unless otherwise so specified.

EXAMPLE 1 One Kg of prilled ammonium nitrate'Icontamirig 312 percent by weight, of water was aerated at C., and 5% %H, in a velocity of 1.5 m/sec. for 20 minutes. An aqueous solution of 3%, by weight, of drying agent as shown in Table i was added thereto by spraying under mixing in a pan type pelletizer. Next, the mixture was dried by fluidized treatment under the same conditions 55in the above aeration for 20 minutes and then was fluidized in a stream of dehydrated air at 15C. for 10 45 minutes where it was cooled at room temperature. To

the prilled ammonium nitrate thus obtained, 0.1 percent, by weight, of magnesium stearate and 0.1 percent, 5y wa ssrrizmn'saranin (lip. cs 300C, in.p. less than -30C.) were admixed to form suitable samwere determined, and the result is reported in Table I.

TABLE I Water Anticontent Amount Antlscnt- (wt. added caking tering per- Drying aid (00.) (percent) grade cunt) Stearyl trimethyl ammonium chloride 20 1 0. 028 Poiyoxy ethylene stea iether 20 06 1 0. 025 Polyoxy ethylene nony phenylether. 20 96 1 0. 021 Laurylaicohol sodium sulfate ester- 20 94 1 0. 032 Polyoxyethylene octylamide. 20 95 1 0. 027 Polyoxyethylene sorbitan monooleate- 20 94 1 0. 035 Polyoxyethylene hydroxypropylene trioi 20 93 1 0.039 Hydroxyethylene-hydroxy-prop ylene block copolymer 20 95 1 0.032 Laurylpicolinium chloride 20 96 1 O. 021 Polyoxyethylene octedecyiamine. 20 93 1 0. 039 Lauryl betain 20 93 1 0. 031 Sodiumsulionate oleic acid amid 20 96 1 0. 024 Polyethyieneglycol monostearate. 20 95 1 0. 033 Sorbitan monooleate 20 92 1 0. 046 Acetylpyridium chloride. 2O 94 1 0. 037 Octadecyiamine butyrate 20 1 0.036 Dodecyiamine butyrate 20 99 1 0.021 Oetyiamine butyrate 20 99 1 0.030 10% aqueous suspension of dode lamina 20 100 1 0. 046 Octadeeylanune nitrate 20 98 1 0. 026 No additive (control) 0 0 1 1. 860

EXAMPLE 2 Prilled ammonium nitrate containing 3.4 percent, by weight, of water was aerated at thetemperature and time as shown ir Table, and then 20 cc. of an aqueous solution of 3 percent, by weight, of octadecylamine nitrate (Sample Nos. l to 6) or dodecylamine nitrate (Sample NOS. 7 to were added thereto by spraying while mixing in pan type pelletizer. After fluid drying with air of 1.5 m/sec. at a velocity under the conditions as shown in Table ii, the mixture was fluidized in a stream of dehydrated air at about mifiiii' to effect cooling at room temperature. To the dried,

prilled ammonium nitrate, thus obtained, 0.1 percent,

by weight, of magnesium stearate and 0.1

weight if liquid paraffin (b.p. Ca 300 c; lTLp. less than 30C) were added and mixed to form the samples. These samples were subjected to the same tests as in Example 1 to give the results as shown in Table ll.

percent, by '15 trate, thus obtained, 0.1 percent, by weight, of magnesium stearate and 0.1 percent, by weight, of liquid paraffin (b.p. Ca 300C, m.p. less than -30C.) were added and mixed to form samples. These samples were subjected to the same tests as in Example 1 with the results as shown in Table III.

Une Kg of prilled ammonium nitratecontainiiig'3 I4' percent, by weight, of water was dried at 70C. for 30 minutes after adding 4 g. of octadecylamine nitrate as TABLE II Aeration Drying Water Anticontent Sample Temp. Time Temp. Time Anti'caking scattering wt. 1 0. 0.) (min.) 0.) (min.) percentage grade percent) EXAMPLE 3 a 4 percent aqueous solution. it was then fluidized in a we'ig'bipriild aiiiifiofiiuiiiiiiirate cofitaiiiing' 5'11" percent, by weight, of water was aerated at 80C. for 20 minutes, and then 15 cc of an aqueous solution of 4 percent, by weight, of octadecylamine nitrate was added thereto by spraying while mixing, in a pan type of pelletizer and the mixture was subjected to aging for the times shown in Table Ill. Next, after drying by passing air at 80C. in '5 line velocity of 1.5 m/sec. for 20 minutes, the mixture was fluidized in a stream of dehydrated air at about 15C. for 10 minutes to effect cooling at room temperature. To the prilled ammonium nistream of dehydrated air at 15C. for 10 minutes to effect cooling at rgomternpggatpre. After adding I 'g. of liquid paraffin (b.p. Ca 300C, m.' 5.lss"f1'i'ii 30c. to the prilled ammonium nitrate, thus obtained, while mixing in a pan type pelletizer, an anti-caking agent, as shown in Table IV was added thereto and mixing was continued for more than fit dilutes to prepare Sample A. For comparison, Sample B was similarly prepared without adding a petroleum hydrocarbon. The anticaking percentage, anti-scattering percentage and adhering percentages were determined on these samples, with the results as shown in Table IV.

TABLE IV Anti-eaking agent Added Anti-eaking amount percentage Anti-scattering grade t. Adhering Kind percent) Sample A Sample B Sample A Sample B percentage Magnesium stearate O. 1 87 80 1 5 97 D0 0.2 93 86 1 5 95 D0 0.5 100 100 1 5 92 Copper stearate- 0. 1 80 71 1 5 95-97 Zinc stearate 0.1 78 70 1 5 95-97 Calcium stearate. 0. 1 60 1 5 95-97 Lead stearate 0. 1 51 l 5 95437 Aluminum stearate 0.1 80 70 l 5 95417 Barium stearate 0.1 40 3G 1 5 95-97 Cadmium stearate. 0. 1 50 42 1 5 95-97 Magnesium caprate. 0. 2 70 G0 1 5 05-97 Magnesium undeanate 0. 2 60 50 1 5 05-07 Magnesium alumlnate sili 0.5 85 1 5 02 (A1203-MgO-2SlQz-4Hz0)- 0. 1 20 15 1 5 -97 Methylene blsstearoamlde. 0. 5 100 2 5 93 Do 0. 1 85 70 1 5 95 Ethylene blsstearoamlde 0. 5 100 97 1 5 92 Methylene bispalmethylamlde 0.5 100 93 1 5 92 Methylene biscnprilamide 0.5 93 93 1 g 92 .0 0

No additive TABLE V Petroleum Anti-caking Antiscattering Adhering hydrocarbon percentage percentage percentage Liquid petrolatum (m.p. 44C., b.p. more than 96 l 97 320C.) No additive V 87 5 60 Molten solid paraffin (m.p. 50C., b.p. 300 to 380C.) 87 3 74 All tests on anti-caking percentage, anti-scattering percentage and adhering percentage of fine powder described in the Examples were conducted by the following methods:

1. Anti-scattering percentage of fine powder I Five hundred g. of sample prepared in each eggarnple are allowed to naturally fall from a height of 0.5 meter onto a screen of 3 mm. and the scattering state of fine powder was rated by the following five grades:

1. No scattering;

2. Slight scattering;

3. Scattered;

4. Vigorously scattered; and

5. Extremely vigorously scattered.

2. Anti-caking percentage intoa highly rigid polyvinyl chloride vessel (qb 10 X h 10 cm) and, after placing a load of 0.2 Kglcm was sealed by a polyethylene bag. The sample was sub- Fee to a thermal e me t s idavs, the tasti temperature being raised from 20 to 45C. over a period of half a day and then reduced again to 20C. over another one-half day. After the above mentioned treatment, the sample was broken by means of a Tensilon (UTM-lll type made by Toyo Sokki Co.). Anti-caking percentage is indicated by the destructive load required percent when load Kglcrn 55:1'0 553cm when 5 st 3. Adhering percentage gS ample prepared in each example is sifted through a 0.42 mm screen. The adhered amount of anti-caking agent is measured on the sample of the above screen by Three hundred g. of sample prepared are introduced atomic absorption analysis, and then the proportion of the amount to that of charged anti-caking is given with percentage.

Having now fully described the invention, it will be 5 apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit or scope of the invention as set forth herein. Accordingly,

What is claimed and intended to be covered by Let- 10 ters patent is:

1. A prilled ammonium nitrate composition having improved anti-caking and anti-scattering properties which comprises a blend of prilled ammonium nitrate 5 with (l) a petroleum hydrocarbon having a boiling point of greater than 150 C and a melting point of less than C and (2) at least one anti-caking agent selected from the group consisting of:

a. magnesium, barium, lead, calcium, zinc, copper, aluminum and cadmium salts of fatty acid having 20' W seven to 2 2 carbon atoms and a mating poirit of more than 40 C; b. magnesium aluminate silicate; and c. a compound represented by the formula:

melting point 6r lessThan 0 C.

4. The prilled ammonium nitrate composition of claim 1, wherein said anti-caking agent is selected from the group consisting of magnesium-, copper-, zinc-, calcium-, lead-, aluminum-, barium, and cadmiumto break the sample thus obtained with antr-cakrngi0 0 stearates, magnesium caprate, and magnesium undecamate.

5. The prilled ammonium nitrate composition of claim 4, wherein said anti-caking agent is magnesium stearate. 

2. The prilled ammonium nitrate composition of claim 1, wherein said anti-caking agent is blended in amounts of 0.01 to 0.5 percent based on the weight of prilled ammonium nitrate.
 3. The prilled ammonium nitrate composition of claim 1, wherein said petroleum hydrocarbon has a melting point of less than 0*C.
 4. The prilled ammonium nitrate composition of claim 1, wherein said anti-caking agent is selected from the group consisting of magnesium-, copper-, zinc-, calcium-, lead-, aluminum-, barium-, and cadmium-stearates, magnesium caprate, and magnesium undecanate.
 5. The prilled ammonium nitrate composition of claim 4, wherein said anti-caking agent is magnesium stearate. 